NF‐κB‐ and c‐Jun‐dependent regulation of human cytomegalovirus immediate‐early gene enhancer/promoter in response to lipopolysaccharide and bacterial CpG‐oligodeoxynucleotides in macrophage cell line RAW 264.7

Abstract

The cytomegalovirus immediate-early (CMV IE) gene enhancer/promoter regulates the expression of immediateearly gene products and initiation of CMV replication. TNF-a and lipopolysaccharide (LPS) strongly activate the promoter, possibly involving NF-jB. CpG-oligodeoxynucleotides (CpG-ODNs), which contain unmethylated CpG dinucleotides in the context of particular base sequences, have gained attention because of their stimulating effects, via NF-jB, which have a strong innate immune response. To study the effects of LPS and CpG-ODNs, as well as the mechanisms of their actions regarding CMV IE enhancer/promoter activation, we used a macrophage cell line, RAW 264.7. Stimulation of the cells with LPS or CpGODNs resulted in the activation of the CMV IE enhancer/ promoter. We examined the involvement of NF-jB and c-Jun transcription factors by promoter deletion/site-specific mutation analysis and ectopic expression, and found them to have additive effects. Involvement of myeloid differentiation protein, an upstream regulator of NF-jB and c-Jun, was also investigated. Experimental results indicate that both LPS-induced and CpG-ODN-induced activations of CMV IE enhancer/promoter are mediated by Toll-like receptor signaling molecules. Several lines of evidence suggest the potential contribution of bacterial infection in CMV reactivation along with the potential application of CpGODNs in gene therapy as a stimulator for the optimal expression of target genes under the control of the CMV IE enhancer/promoter.

Mouse cytomegalovirus inhibits beta interferon (IFN-β) gene expression and controls activation pathways of the IFN-β enhanceosome

“…Given the proviral capabilities of ATF-2/c-Jun, as observed in the context of influenza virus infection (Ludwig et al, 2001), it is conceivable that ATF-2/c-Jun transcription is also exploited by MCMV to enhance replication efficiency. Compatible with this idea, earlier reports confirmed c-Jun to be involved in regulation of CMV ie transcription (Lee et al, 2004;Wang & Sonenshein, 2005). Nonetheless, the cellular components responsible for IFN-a/b induction by replicating MCMV lying upstream of the transcription factors are not clear.…”

Renal Ischemia/Reperfusion Injury Activates the Enhancer Domain of the Human Cytomegalovirus Major Immediate Early Promoter

“…The HCMV MIEP has four CRE elements, two TPA response elements (TRE) and four NF-jB consensus sites, and numerous studies have implicated these sites as being important in regulation of the gene (25)(26)(27)(28)(29)32,33,(38)(39)(40)(41). NF-jB is activated by inflammatory stimuli, including TNF, IL-1, and LPS and by oxidative stress (21)(22)(23)42,43).…”

“…The HCMV MIEP has four NF-jB consensus binding sites which are important in regulation of ie gene expression (25)(26)(27)(28)(29). NF-jB is activated by oxidative stress and by inflammatory stimuli, including TNF.…”

Gemcitabine synergistically enhances the effect of adenovirus gene therapy through activation of the CMV promoter in pancreatic cancer cells

“…[25][26][27] Therefore, we investigated the effects of GEM on NF-kB activity by measuring the NF-kB protein levels in the nuclei of GEM-treated cells. GEM-treated cells expressed significantly higher levels of NF-kB in their nuclei than untreated cells (P ¼ 0.03), but the difference was small (data not shown).…”